Although the number of deaths was numerically higher in the Benlysta group in the new study -- 11 vs. 3 in the standard treatment group -- the difference could have been due to chance.
"It is what you expect. It is less than 1% of patients," Merrill says. "You wouldn’t see an effect on mortality in one year."
Harvard Medical School's Elena Massarotti, MD, who moderated the session at which the most recent data were presented, tells WebMD that Benlysta may have a role in the treatment of lupus patients.
The drug met its primary goal in two major studies and seems to have a good safety profile, she says.
The FDA is expected to issue a final decision by Dec. 9.
Epratuzumab Also Shows Promise for Lupus
Also at the ACR meeting, researchers reported on the investigational drug epratuzumab, which is in earlier-stage testing.
In a study of 227 people with moderate to severe lupus, epratuzumab was associated with a meaningful reduction in disease activity compared with placebo, says study leader Daniel Wallace, MD, of the David Geffen School of Medicine at UCLA.
In the 12-week study, the rate of serious side effects, including infections, appeared to be similar among both groups, he says.
Reduced disease activity was seen in as little as eight weeks, according to findings of the study, which tested a variety of doses of epratuzumab.
Epratuzumab is a monoclonal antibody that targets the CD22 molecule, which is thought to be a regulator of B cells that contribute to lupus by producing antibodies against the body's own tissues. This, in turn, causes the immune system to turn on itself, resulting in inflammation and tissue damage.
Commenting on the findings, Merrill says, "This was a very important study" that tells researchers the best dose to use as they move into large-scale testing required for FDA approval.
Future research, she adds, will include finding out whether the treatment can help spare the use of steroids in patients.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.